Phosphotungstic Acid Research Articles

Enhanced NOx reduction on CePO4 catalysts: Cu-loading, phosphotungstic acid, and insights from In-situ DRIFTs and DFT

This study investigates the effects of varying Cu/Ce doping ratios on the NH3-SCR denitrification efficiency using Cu-HPW/CePO4 catalysts, where CePO4 serves as the support and copper-doped phosphotungstic acid (HPW) acts as the active phase. The NH3-SCR reaction mechanism was studied by In-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (In-situ DRIFTs) and Density Functional Theory (DFT). In-situ DRIFTs were employed to delve into the intricacies of adsorption and transformation dynamics at the surface sites of catalysts. This approach furnished a robust theoretical foundation aimed at augmenting the efficacy of low-temperature denitrification catalysts. DFT calculations were used to systematically investigate the reaction pathways, intermediates, transition states, and energy barriers over the HPW structure model to complete the NH3-SCR reaction. Empirical evidence suggests that modifying the catalysts with copper substantially enhances their denitrification efficacy and extends their operational temperature spectrum. A notable initial increase in denitrification efficiency was observed with increasing levels of copper modification, followed by a decline. Within the HPW-O15H site, the NH3-SCR reaction advances through both the E-R and L-H mechanisms, encompassing processes such as NH3 adsorption, intermediate formation and transformation, and product release.

Screening staining agents for contrast-enhanced microCT of vascular tissues: Assessing the effect on microstructural and mechanical properties

Cardiovascular tissues possess a complex microstructure, which remodel and adapt due to ageing and diseases. This complex and evolving microstructure is intrinsically linked to the tissue’s mechanical properties. To better understand how changes in the microstructure can impact the mechanical behavior, 4D-contrast-enhanced microCT (4D-CECT) can be used (i.e. in situ mechanical loading combined with 3D microstructural visualization). Since absorption-based CECT requires the use of contrast-enhancing staining agents (CESAs), we investigated six different CESAs for their suitability for 4D-CECT imaging of arterial tissue, considering their ability to provide good microstructural visualization and segmentation while ensuring the preservation of the mechanical properties. For this purpose, the penetration speed, contrast-enhancement, volume change, and stiffness change of porcine arterial tissue stained with the different CESA solutions were studied. Based on our results, we selected 1:2 Hafnium-substituted Wells-Dawson Polyoxometalate as the most suited CESA for 4D-CECT of arterial tissue. Phosphotungstic acid (PTA) and Lugol iodine with Sorensen’s buffer (Lugol), despite being the reference in the state-of-the-art as CESA and having excellent contrast-enhancement properties, were the only ones that significantly affected the mechanical properties of porcine arterial tissue. Additionally, for these two solutions, tissue shrinkage was observed, resulting in a volume reduction of approximately − 12 % for PTA and − 17 % for Lugol. Finally, it was observed that the penetration speed of all CESA solutions exhibited a ratio of 60–40 % from the intimal side to the adventitial side, which is likely due to the denser packing of elastic lamellae towards the adventitia. Overall, our study offers valuable new insights for selecting and comparing various CESA solutions for (4D-)CECT.

Sorption enhanced DME synthesis by one-step CO2 hydrogenation

DME synthesis by direct CO2 hydrogenation was studied on physical mixture of commercial CuZnO/Al2O3 (CZA) and in-house synthesized PTA (phosphotungstic acid)/γ-Al2O3 catalysts. Effects of PTA loading (0–50 % by mass) and relative amounts of the catalysts on CO2 conversion and DME yield were investigated. The process was intensified through integration of in-situ steam separation by Zeolite 3A (Z3A) adsorbent mixed with the catalysts. Experiments were run at 498 K, 30 bar, H2:CO2=3:1 and GHSV=1750 h−1 (based on CZA catalyst). Optimum PTA loading and CZA:PTA/γ-Al2O3 mass ratio were 30 % and 1:2, respectively, that gave ∼21 % CO2 conversion and 6.3 % DME yield. These values remained below the respective thermodynamic limits (28.5 % and 21 %), which were exceeded upon adsorbent integration. Catalytic performance depended strongly on adsorbent quantity studied at the catalyst (CZA+PTA/γ-Al2O3):adsorbent mass ratio range of 1:0.33–4. Catalysts and the adsorbent remained stable during the pressure swing driven adsorption-regeneration cycles. Sorption assistance at catalyst:adsorbent ratio=1:4 increased catalyst productivity from 5.5×10−3 to 2×10−2 kgDME h−1 kgcat−1. The latter value was comparable to those of the sorption enhanced CO2+CO hydrogenation systems due to the PTA-based dehydration catalyst with strong acidic features and was promising when the strong thermodynamic limitations of CO2-DME conversion was considered.

Synergistic Enhancement of Supercapacitor Performance: Vanadium‐Substituted Phosphotungstic and Molybdic Acid Combined with Polypyrrole Using Pyridinium and Ammonium Ionic Containing Organic Cation Linkers with Improved Conductivity

High‐performance energy‐storage devices have emerged as a favored choice owing to their remarkable efficiency, sustainability, and environmental friendliness. Nowadays, polyoxometalate (POM)‐based supercapacitor (SC) electrode materials have gained much attention. Herein, a few new POMs and ionic liquid (IL) composites incorporated into conducting polymer as electrode materials for SC applications are reported. The H6[PV3Mo9O40]⋅34H2O (PV3Mo9) and H6[PV3W9O40].34H2O (PV3W9) POMs are treated with tetrabutylammonium chloride and 1‐butyl‐4‐methyl pyridinium chloride (BMP) and finally combined with polypyrrole (PPy) for the SC studies. An extensive array of analytical techniques is employed to delve into the interplay between the constituents within the composite materials, such as Fourier transform infrared spectroscopy, powder X‐ray diffraction, thermogravimetric analysis, nuclear magnetic resonance (1H and 13C), Field‐emission scanning electron microscopy, energy‐dispersive X‐ray stpectroscopy, X‐ray photoelectron spectroscopy, and Brunauer‐Emmett‐Teller surface area. The combined application of these techniques enables us to understand the interaction dynamics within composite materials comprehensively. POM–ILs combination improves the solubility issues of POMs, and doping of PPy enhances the electrochemical performances of the materials. The PV3W9–BMP–PPy symmetric SC cell shows a specific capacitance of 294.79 F g−1 and an energy density of 28.89 Wh kg−1 at 1 A g−1 current density in 0.25 M H2SO4 medium followed by an excellent cycle life of 78.6% after 10,000 galvanostatic charge–discharge cycles. The fabricated SC device is performed to light up the bulbs of red, yellow, and green light emitting diodes for 50, 30, and 28 s, respectively.

β stimulator induces upregulation of miR-27a in the rat heart one hour after the injection

MicroRNAs (miRs) are non-coding small RNA containing 18 to 22 nucleotides, that post-transcriptionally regulates mRNA expression. Chronic injection of β stimulator is known to induce cardiac injury and change of miRs expression level in the heart with some pathological changes such as fibrosis, heart failure, myocardial infarction. We investigated the changes in the expression level of miRs in the rat heart one hour after isoproterenol (a β stimulator) injection.Male Sprague-Dawley rats were assigned into three groups and received subcutaneous injection of normal sarin (NS) or 0.1 mg/kg isoproterenol (ISO-0.1) or 10 mg/kg isoproterenol (ISO-10). After one hour, we collected their heart and plasma. Total RNA was extracted from the left ventricle and used for deep miRNA sequencing. Based on the results of miRNA sequencing, we performed real-time polymerase chain reaction (RT-PCR) using 8 miR primers. Cardiac injury was evaluated by hematoxylin and eosin, and phosphotungstic acid–hematoxylin staining and measuring troponin-I levels in plasma.Troponin-I was significantly increased in ISO-0.1 and ISO-10 groups, but histological observation did not show any cardiac necrosis. miRNA sequencing identified 14 upregulated miRs and 12 downregulated miRs. Of the 26 miRs, RT-PCR confirmed miR-144-3p/5p and miR-451-5p were decreased, and that 5 miRs (miR-27a-5p, miR-30b-3p, miR-92a-1-5p, miR-132-5p, miR-582-3p) were upregulated.This study showed that β stimulus causes downregulation of miR-144/451 cluster and increases expression of five 5 miRs in the heart, especially 6.5-fold upregulation of miR-27a-5p as early as one hour after isoproterenol injection. Therefore, these miRs might be good biomarkers for cardiac injury.

Transparent insulating photochromic PU/PTA films for Wide-Spectrum modulated smart windows

Photochromic materials have recently attracted widespread attention in the research of smart windows because they can function without additional devices. In this study, an innovative photochromic thermal insulating hybrid film based on a polyurethane matrix was prepared via a one-pot method, incorporating phosphotungstic acid. The film demonstrates excellent transparency, good mechanical strength, and a significant modulation of the solar spectrum, transitioning from colorless to dark blue under sunlight without the need for additional electron donors. This photochromic behavior is reversible and reproducible without degradation, resulting in a transmittance variation of up to 71 % at 550 nm, which is the most sensitive to the human eye, and more than 50 % modulating performance in 1800 ∼ 2500 nm. In addition, thermal insulation experiments proved that the smart window device prepared by the film could achieve a reduction of 9.3 °C under daylight. Overall, the photochromic films prepared using the one-pot method show good performance involving mechanical strength, efficient photochromic response, broad spectral range modulation, high coloring efficiency and cycling stability, and have promising applications in energy-saving buildings, anti-counterfeiting and smart displays.

Production of diphenolic acid from bio-levulinic acid over MCF supported bimetallic phosphotungstic acid as catalyst: Enhancement in rate and selectivity under microwave irradiation

The para-isomer of diphenolic acid is widely accepted as a bio-based polymer precursor and a sustainable substitute for bisphenol A (BPA). In the current work, a bimetallic dodecatungstophosphoric acid salt catalyst supported on mesocellular foam (MCF) was employed to condense bio-derived levulinic acid and phenol under solvent-free conditions in the presence of microwaves to enhance rates of reaction, conversion and selectivity. Various parameters affecting conversion and selectivity were systematically studied. A study was done to investigate the factors that affect the reaction rate. A kinetic model was derived, and reaction mechanism proposed. The reaction proceeds with a second-order kinetics with an activation energy of 10.17 Kcal/mol and exhibits the Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism. The catalyst was robust and could be repeatedly used. The overall process showed microwaves coupled with the new catalyst improved efficiency, selectivity, and sustainability in synthesizing diphenolic acid (DPA), offering new insights into the process.

S-scheme heterojunction phthalocyanine/TiO2 photoelectrochemical sensor for innovative glutathione detection.

A novel photoelectrochemical sensor, employing an S-scheme heterojunction of phthalocyanine and TiO2 nanoparticles, has been developed to enable highly sensitive determination of glutathione. By integrating the favorable stability, environmental benignity, and electronic properties of the TiO2 matrix with the unique photoactivity of phthalocyanine species, the designed sensor presents a substantial linear dynamic range and a low detection limit for the quantification of glutathione. The sensitivity is attributed to efficient charge transfer and separation across the staggered heterojunction energy levels, which generates measurable photocurrent signals. Systematic variation of phthalocyanine content reveals an optimal composition that balances light harvesting capacity and electron-hole recombination rates. The incorporation of phosphotungstic acid (PTA) in sample preparation effectively minimizes interference from compounds like L-cysteine and others. Consequently, this leads to an improvement in accuracy through the reduction of impurity levels. Appreciable photocurrent enhancements are observed upon introduction of both oxidized and reduced glutathione at the optimized composite photoanode. Coupled with advantageous features of photoelectrochemical transduction such as simplicity, cost-effectiveness, and resistance to fouling, this sensor holds great promise for practical applications in complex biological media.

Low-cost and green straw derived hierarchical porous carbon as support to phosphotungstic acid for efficient and clean production of α-terpineol

This study developed a novel reciprocal template method to prepare MgO@Carbon micrometre tubes directly from straw-based biomass. Biomass carbon with a rich hierarchical porous structure (MRSC30) was obtained by acid-washing the MgO@Carbon micrometre tubes. The pore formation mechanism of MRSC30 was systematically analyzed using Density Functional Theory calculations and various characterization methods. The in situ growth of Mg(OH)Cl/MgO inside the biomass promotes the polymerized carbon precursors to be tightly affixed to the templating agent and provides exfoliation, support, and catalysis (i.e., electrostatic attraction, nucleophilic substitution, and electrophilic addition), which effectively promotes the formation of hierarchical porous carbon. The continuous release of light gases from the inside out during the prolongation of the decomposition temperature of the biomass by Mg(OH)Cl or/and MgO helps to promote the formation of stomata in the biomass carbon. The results showed that the method minimized the consumption of chemicals, energy consumption, and the time required to prepare HPC by 35.75%, 67.57%, and 52.38%, respectively. The phosphotungstic acid-loaded MRSC30 was successfully prepared as a highly amphiphilic and highly acidic solid acid catalyst and applied to the hydration of α-pinene to prepare superior performance gasoline additives (α-terpineol). Under optimal process conditions obtained in a batch reactor, the catalytic performance of the catalyst could be further improved by alternating flow using a novel semi-batch unsteady-state reactor developed in this institute, and the α-pinene conversion and the α-terpineol selectivity reached a maximum of 95.53% and 65.75%, respectively. At the same time, the reactor was able to substantially reduce the time required for hydration and the amount of moderately toxic acetone used compared to the conventional batch reactor by 20.83% and 62.50%, respectively.

NiFe layered double hydroxide nanosheets self assembled and etched by phosphotungstic acid for the enhanced oxygen evolution reaction

Poor conductivity and low reaction kinetics of layered double hydroxides (LDHs) hindered their large-scale applications as catalysts in the oxygen evolution reactions (OER). The composites with vacancies, high valence cations and 3D gradient pore structures were synthesized by the ionic exchange, delamination and self-assembly methods. The nanoclusters [PW12O40]3- were successfully intercalated into the interlayers of LDHs due to the static attraction. Meanwhile, the partial metal cations in the layers were etched by its conjugate acid. The molar ratios of Ni:Fe and acid:LDH need to be modulated to achieve the optimum catalytic performances. The composite 1:4PW12–Ni3Fe exhibited a lower overpotential 270 mV at 10 mA cm−2, superior kinetics (43 mV dec−1), better conductivity (2.68 Ω cm−2) and larger turnover frequency (3.59 s−1) than the bulk and nanosheet counterparts with reevesite-like structure. [PW12O40]3- more effectively reduced the overpotentials of LDHs than other interlayer anions (e.g.WO4−, B4O72− and CnH2n+1SO42−). The favourable electrocatalytic performances were attributed to the synergistic effects. The vacancies provided new active centers with high intermediate adsorption energy. The high valances cations induced electronic coupling and spatial charge redistribution. 3D gradient pore structures with a large electrochemical active surface area exposed active sites and provided a convenient path for transferring masses and charges.

Esterification catalytic over Imidazolium Ionic Liquid Modified salt of phosphotungstic Acid catalyst

A solid acid was prepared by the reaction of phosphotungstic acid (HPW)with 1-methy- limidazolium sulfobutyrolactone (MIMSB) and characterized by the methods of X-ray powder diffraction, FT-IR, potentiometric titration and SEM. Then the solid acid was employed for esterification to evaluate its acid-catalytic activity. Various reaction parameters, including catalyst dosage, reaction time, n-butanel/butyric acid molar ratio and reaction temperature were systematically examined. These results indicated that the prepared catalyst maintained the Keggin structure of the raw HPW, and had high acidity. The catalyst exhibited excellent catalytic activity in esterification of n-butyric acid and n-butanol.93. 4% conversion of n-butyric acid was obtained under the optimized reaction conditions. The catalyst also had good stability.

A Low-Temperature Solution-Processed Nickel Oxide Nanoparticles and Phosphotungstic Acid Composite as an Anode Interface Layer for Organic Solar Cells

A Low-Temperature Solution-Processed Nickel Oxide Nanoparticles and Phosphotungstic Acid Composite as an Anode Interface Layer for Organic Solar Cells

Detailed Study on the Interfacial Interaction between Different Polyoxometalates and Tetronic Block Copolymers Exploring the Langmuir-Blodgett Technique.

Polyoxometalates (POMs) interact with various biologically relevant entities. A basic understanding of this interaction is very important for various applications in the biological field. In this work, the focus is on the study of the interaction between tetronics and Keggin POMs. T701 and T90R4 are the two tetronics considered here; they have different solubilities in water due to different PPO/PEO ratios. The arrangement of PPO and PEO is also different with respect to the central ethylenediamine groups. Three different Keggin-type POMs, phosphomolybdic acid (PMA), phosphotungstic acid (PTA), and silicotungstic acid (STA), with different charge densities are chosen for an elaborate investigation using Langmuir-Blodgett technique. The observation is analyzed thoroughly, which shows both electrostatic interaction and adsorption of POMs on the PPO blocks of the tetronics due to the chaotropic effect, which is responsible for the binding of POMs (in subphase) with the tetronic monolayer. This interaction results in an expanded yet rigid monolayer for POM-tetronic association on the surface. Surface pressure vs mean molecular area isotherm is the key characterization to reach the conclusion. UV-vis spectroscopy, NMR, ITC, ellipsometric studies, FTIR, and SEM also serve as supportive characterization techniques.

Antimicrobial Susceptibility Testing for Colistin: Extended Application of Novel Quantitative and Morphologic Assay Using Scanning Electron Microscopy.

Colistin (Polymyxin E) has reemerged in the treatment of MDR Gram-negative infections. Traditional Colistin AST methods have long turnaround times and are cumbersome for routine use. We present a SEM-AST technique enabling rapid detection of Colistin resistance through direct observation of morphological and quantitative changes in bacteria exposed to Colistin. Forty-four Gram-negative reference organisms were chosen based on their Colistin susceptibility profiles. Bacterial suspensions of ∼107 CFU/mL were exposed to Colistin at EUCAST-ECOFF, with controls not exposed, incubated at 37°C, and then sampled at 0, 15, 30, 60, and 120 minutes. Phosphotungstic Acid (PTA) staining was applied, followed by SEM imaging using Hitachi TM4000PlusII-Tabletop-SEM at ×2000, ×5000 and ×7000 magnifications. Bacterial viability analysis was performed for all conditions by quantifying viable and dead organisms based on PTA-staining and morphologic changes. We identified a significant drop in the percentage of viable organisms starting 30 minutes after exposure in susceptible strains, as compared to nonsignificant changes in resistant strains across all tested organisms. The killing effect of Colistin was best observed after 120 minutes of incubation with the antibiotic, with significant changes in morphologic features, including bacterial inflation, fusion, and lysis, observed as early as 30 minutes. Our observation matched the results of the gold standard-based broth microdilution method. We provide an extended application of the proof of concept for the utilization of the SEM-AST assay for Colistin for a number of clinically relevant bacterial species, providing a rapid and reliable susceptibility profile for a critical antibiotic.

Phosphotungstic Acid Clusters Decorated Znln2S4 Nanoflowers as Molecular-Scale S-Scheme Heterojunctions for Simultaneous H2 Evolution and Benzyl Alcohol Upgrading.

Simultaneous utilization of photogenerated electrons and holes to achieve overall redox reactions is attractive but still far from practical application. The emerging step (S)-scheme mechanism has proven to be an ideal approach to inhibit charge recombination and supply photoinduced charges with highest redox potentials. Herein, a hierarchical phosphotungstic acid (H3PW12O40, HPW)@Znln2S4 (ZISW) heterojunction was prepared through one-pot hydrothermal method for simultaneous hydrogen (H2) evolution and benzyl alcohol upgrading. The fabricated HPW-based heterojunctions indicated much enhanced visible-light absorption, promoted photogenerated charge transfer and inhibited charge recombination, owing to hierarchical architecture based on visible-light responsive Znln2S4 microspheres, and S-scheme charge transfer pathway. The S-scheme mechanism was further verified by free-radical trapping electron spin resonance (ESR) spectra. Moreover, the wettability of composite heterojunction was improved by the modification of hydrophilic HPW, contributing to gaining active hydrogen (H+) from water sustainably. The optimal ZISW-30 heterojunction photocatalyst indicated an enhanced hydrogen evolution rate of 27.59 mmol g-1 h-1 in benzyl alcohol (10 vol. %) solution under full-spectrum irradiation, along with highest benzaldehyde production rate is 8.32 mmol g-1 h-1. This work provides a promising guideline for incorporating HPW into S-scheme heterojunctions to achieve efficient overall redox reactions.

Optimization of Desulfurization Process via Choline Phosphotungstate Coupled with Persulfate Using Response Surface Methodology

Using a simple acid-base neutralization method, a Ch-PW solid catalyst was synthesized by mixing choline hydroxide (ChOH) and phosphotungstic acid (HPW) at a 2:1 molar ratio in an aqueous solution. This catalyst was combined with a 20 wt.% potassium peroxymonosulfate (PMS) solution, using acetonitrile (ACN) as the extraction solvent to create an extraction catalytic oxidative desulfurization system. The optimal desulfurization conditions were determined through response surface methodology, targeting the highest desulfurization rate: 0.99 g of Ch-PW, 1.07 g of PMS, 2.5 g of extraction solvent, at a temperature of 50.48 °C. The predicted desulfurization rate was 90.79%, compared to an experimental rate of 93.64%, with a deviation of 3.04%. A quadratic model correlating the desulfurization rate with the four conditions was developed and validated using ANOVA, which also quantified the impact of each factor on the desulfurization rate: PMS > ACN > Ch-PW > temperature. GC-MS analysis identified the main oxidation product as DBTO2, and the mechanism of desulfurization in this system was further explored.

High-performance proton exchange membrane employing water-insoluble hybrid formed by chemically bonding phosphotungstic acid with polydopamine

Heteropolyacids can retain water in a proton exchange membrane to increase proton conductivity at high temperatures and low humidity; however, their high solubility in water leads to leaching, which limits their further application. Herein, we used phosphotungstic acid (HPW) and polydopamine (PDA) particles to prepare a water-insoluble PDA/HPW hybrid (PDW) via hydrothermal reaction. The amino groups of PDA in PDW chemically bonded to HPW and acted as an anchor for HPW. The proton conductivity of the sulfonated poly(ether ether ketone) (SPEEK) composite membrane containing 15wt% PDW (SPEEK/PDW-15) in liquid water was 0.052 S⸱cm–1 at 25 ℃, which was 63% higher than that of the SPEEK control membrane (0.032 S⸱cm–1). The SPEEK/PDW-15 composite membrane also showed stable proton conductivity during 80 days of testing while immersed in water.

Electrostatic interactions mediated defibrillation of β-lactoglobulin fibrils using Keggin Polyoxometalates

The whey protein β-lactoglobulin (βLG) forms fibrils similar to the amyloid fibrils in the neurodegenerative diseases due to its higher predisposition of β-sheets. This study shed light on the understanding different inorganic Keggin polyoxometalates (POMs) interaction with the protein βLG fibrils. POMs such as Phosphomolybdic acid (PMA), silicomolybdic acid (SMA), tungstosilicic acid (TSA), and phosphotungstic acid (PTA) were used due to their inherent higher anionic charges. The interaction studies were monitored with fluorescence spectra and Thioflavin T assay for both the βLG monomers and the fibrils initially to elucidate the binding ability of the POMs. The binding of POMs and βLG is also demonstrated by molecular docking studies. Zeta potential studies showed the electrostatic mediated higher interactions of the POMs with the protein fibrils. Isothermal titration calorimetry (ITC) studies showed that the molybdenum containing POMs have higher affinity to the protein fibrils than the tungsten. This study could help understanding formation of food grade protein fibrils which have profound importance in food industries.

WC nanoparticles and NiFe alloy co-encapsulated in N-doped carbon nanocage for exceptional OER and ORR bifunctional electrocatalysis

Developing earth-abundant electrocatalysts with optimized intrinsic active sites is crucial for enhancing bifunctional oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) performance. In this study, we fabricated a hollow structured carbon framework utilizing NiFe Prussian Blue analogs (PBAs) as templates, while polypyrrole (PPy) and phosphotungstic acid (PW12). Pyrrole monomer underwent polymerization on the nanocubic PBA surface in the presence of PW12 (PBA@PPy-PW12). Subsequent carbothermal reduction created an N-doped carbon shell with embedded NiFe alloy and tungsten carbide (WC) nanoparticles. The polymeric PPy-PW12 nature can not only prevent the aggregation of PBA and WC structures but also enhance electrical conductivity by connecting neighboring nanospheres. Moreover, the introduction of WC can significantly enhance the bifunctional electrocatalytic activity of the carbon-based catalyst, which is attributed to synergism between the WC and NiFe materials within the NC layer. Consequently, NiFe/W0.3C@NC exhibited outstanding OER (overpotential = 290 mV for 10 mA/cm2; Tafel slope = 57 mV/dec) and ORR (half wave potential = 0.81 V; Tafel slope = 61 mV/dec) performances. This work presents a promising avenue for developing high-performance electrocatalysts for energy conversion systems that showcase remarkable efficiency, stability, and potential practicability.

Modeling and simulation of biodiesel synthesis in fixed bed and packed bed membrane reactors using heterogeneous catalyst: a comparative study

In this study, modeling and simulation of biodiesel synthesis through transesterification of triglyceride (TG) over a heterogeneous catalyst in a packed bed membrane reactor (PBMR) was performed using a solid catalyst and compared with a fixed bed reactor (FBR). The kinetic data for the transesterification reaction of canola oil and methanol in the presence of solid tungstophosphoric acid catalyst was extracted from the published open literature. The effect of reaction temperature, feed flow rate, disproportionation of the reactants, and reactor length on the product performance was investigated. Two-dimensional and heterogeneous modeling was applied to PBMR and the resultant equations were solved by the Matlab software. Moreover, the velocity profile in the membrane reactor was obtained. The results showed the best conditions for this reaction are 180 °C, the molar ratio of methanol to oil equal 15:1, and the input flow rate of 0.5 mL/min. In this condition, a conversion of 99.94% for the TG can be achieved in the PBMR with a length of 86 cm while a length of 2.75 m is required to achieve this conversion of the FBR. Finally, the energy consumption for the production of 8000 ton/y biodiesel in a production plant using the PBMR and the FBR was obtained as is 1313.24 and 1352.44 kW, respectively.